The primary aim of this invention is to provide an aid to enhance the ability of people with tunnel vision, blindness, or other visual disabilities to keep track of their orientation and to orient themselves or their gaze toward targets or paths of interest. The aid is based on an innovative application of head pointing, which not only provides an accessible, hands-free method for input and output, but is also a highly natural and even preferable modality for the type of information relevant to many orientation-related tasks, including searching and scanning, orienting oneself, and recalling directions. The present invention provides an augmentation to the various optical devices, lenses, and prisms currently available, and will also integrate effectively with a variety of indoor and outdoor navigation technologies (GPS, WiFi beacon networks, etc.), which typically have strengths at locating the user and computing optimal routes, but tend to be weaker at providing non-visual guidance on how to proceed. Unlike other high-tech aids, the proposed device requires no cumbersome cameras or head-mounted displays, is inconspicuous, and is of potentially low cost.
Consider the case of a person with extremely limited peripheral vision. The person likely has experienced difficulty in keeping track of where he or she is looking and where he or she is going. Examples of difficulties include: as a student in school, in switching of visual attention between what the teacher had written on the board and the class notebook or, in navigating outdoors, looking at the ground to navigate a curb, then returning the gaze and orientation toward an original goal, such as a crosswalk signal. Such angle-orientation problems extend to large low-vision and blind population.
Problems related to orienting oneself or one's gaze are wide-ranging, and specifics depend on the individual: Tunnel vision is one example. Those with a peripheral visual field of 20 degrees or less are considered legally blind, and at that level of tunnel vision, difficulties are often related to lacking visual cues to direct attention toward objects outside the limited peripheral visual field. Examples include colliding with people approaching from the side, difficulties remembering where objects were placed, etc. At more severely restricted fields, of 5 degrees or less, being able to find things becomes increasingly difficult, even when knowing roughly in what direction they are. Another is an example of not being able to find products—laborious to locate in the first place, on the cluttered shelves of a grocery store after being distracted by a brief conversation. Such individuals spend an inordinate amount of time scanning the visual scene, not to mention encountering obvious safety issues. Among those with low visual acuity or no functional vision, similar problems are encountered. Sometimes people become disoriented inside a store or office, encounter situations of not knowing which direction the front of the store is, or the direction to find the restrooms. There are exciting recreational outcomes for being able to orient one's head accurately as well—for example, the present invention could be used by blind people for bowling.
Review of Existing Solutions to the Problem
This section includes a review of currently-available technology and some approaches in R&D. We conclude that there is a significant unmet need for the functionality available with the present invention.
Compensatory Training
The traditional approach to addressing the problems caused by tunnel vision and blindness is by learning new techniques, such as through orientation and mobility training, learning to scan more efficiently with the available vision, utilizing other senses, etc. Depending on the individual, varying amounts of training and adjustment may be required. Clinicians train visually-impaired users to organize their living and work spaces and to modify everyday activities to make it easier to find things and navigate the environment. Aids such as cane techniques and guide dogs may be applied.
Optical Technologies
Devices such as spectacle-mounted mirrors, reverse telescopes, cemented or press-on prisms, and demagnification or illumination devices are most beneficial for users with reasonable visual acuity and wider existing fields of vision. Those with visual fields from 75 to 120 degrees may be helped with prismatic field-expanding glasses. These optical devices can give tunnel-vision sufferers some amount of peripheral vision, enough to know to turn their heads. Such devices, requiring extensive expert fitting and adjusting, further reduce the available undistorted visual field. Designing such devices for less than a 20 degree visual field usually involves many compromises and is reported to be very complex. Optical techniques alone cannot meet many of the user's needs.
Navigation Technologies
Accessible electronic travel aids such as GPS units and compasses are available—these solve several problems of orientation and navigation over larger distances, but do not provide accurate angular information needed to move directly through cluttered environments or an ability to point in angle and elevation toward objects in close quarters. GPS systems are unreliable in indoor settings, and although indoor technologies are being developed (WiFi hotspots, Bluetooth beacons), these require significant infrastructure and databases that currently don't exist for the vast majority of buildings.
Some technology for guiding a person's attention to an object of interest have been disclosed. For example, U.S. Patent Application 2015/0310657 by Eden discloses using gaze tracking data and moving a visual display item adjacent to the user's gaze toward the target of interest. However, this approach would be difficult for very limited peripheral vision, since it is visual, and would need to stay within a very precise field of view. It also requires wearing a video display. U.S. Patent Application 2016/0080874 by Fullam discloses processing audio information from a microphone array to emphasize sounds coming from a direction of interest. However, it requires mounting an array of microphones to the user and would not work if no sound is coming from the direction of interest. A technical paper “Using 3D Audio Guidance to Locate Indoor Static Objects” by Samuel Sandberg, et al. www.umiacs.umd.edu/˜elm/projects/3daudio/3daudio.pdf) discloses synthesis of a stereo sound that appears to come from the direction of a target. Recent work in human sound perception has yielded an understanding of how to generate directional sounds much more advanced than by simple binaural phase and amplitude manipulations. Especially relevant are Head Related Transfer Function (HRTF) filters that model the user's ears and surrounding anatomy. The “beacon” sound from the target direction of interest can be fed through HRTF filters to produce realistic stereophonic sounds. Review of literature suggests a head-pointing accuracy on the order of 5 to 10 degrees would be available from this technique, but this may be too large for very limited peripheral fields. Additionally, the technique requires the user to wear stereo headphones, which may be inconvenient or dangerous in some situations, and many people have trouble disambiguating HRTF-generated sounds from the front and rear.
Pedometer Technologies.
As will be described below, keeping track of the direction of one's gaze is interrelated with keeping track of one's position. For example, if a person is looking a an object on a shelf, then walks a few steps down the aisle, the correct position for looking at that object will have changed. Therefore, a sensor to measure the distance walked would be helpful as a part of the present invention. One approach to measuring distance walked is to use a stride sensor, or other type of walking-distance sensor, which are referred to here as pedometers.
Most commercially-available pedometers in the art simply count steps, then multiply the number of steps by a fixed average stride length. For example, U.S. Pat. No. 5,117,444 to Sutton et al. describes a electromechancal pedulum-based sensor that swings a magnet past a reed switch as the user walks. Methods are disclosed for computing average stride lengths and calculating distance walked. The device mounts on the user's belt, which typically is a convenient location. U.S. Patent Application 2013/0090881A1 discloses an electronic step-counting technique that uses periodicity of an accelerometer waveform to attempt improved detection of how many steps are walked, allowing for unique walking characteristics. However, for people walking very slowly or demonstrating major differences between steps, such sensors do not always provide accurate measurement. For example, when shopping, stride lengths and acceleration characteristics are likely to vary much more than when doing a fitness walk outdoors.
Other prior-art devices use techniques beyond average step length to attempt to improve step length calculations. For example, in U.S. Pat. No. 7,647,196 to Kahn, discloses measuring additional acceleration values on the user's body to characterize the user's gait into various activity categories, and then a specific step length value from that category is used instead of a global step length over all activities. However, there may still be many variations within a category, and if the user's activity is not part of a pre-stored category, incorrect step lengths might be calculated. This device also requires mounting sensors on a plurality of locations on the body, which may be inconvenient.
Devices have been described to more accurately measure walking distance using other types of sensing. U.S. Pat. No. 6,594,617 to Scherzinger describes sensors on each foot that measure relative distance to a backpack-mounted device to compute walked distance. However, the device requires sensors on each foot, and the backpack device, which may not be user friendly for many people in everyday activities. U.S. Pat. No. 4,371,945 to Karr, et al. discloses ultrasonic sensors on each foot, from which the distance between the feet is used to compute total distance traveled, but also requires multiple sensors to be located on or near the feet. Similarly, U.S. Pat. No. 6,549,845 to Eakle, Jr. et al discloses mounting magnets and magnetometers on the feet or footwear, and measuring the relative distance from the magnetic fields.
Inventions with a sensor on only one foot have also been disclosed. U.S. Pat. No. 6,145,389 to Ebeling et al discloses a single foot-mounted pedometer that computes distance directly from the accelerometer values. This theoretically provides a good technique for measuring distance, but requires a foot-mounted accelerometer, which is often not practical for some people, and is not compatible with some types of footwear that do not have laces or other areas suitable for mounting of sensors.
Some techniques have been disclosed that use accelerometers that are not on the foot and which measure distances better than step counting. “A Step Length Estimation Model for Position Tracking” by Sun, et. al (International Conference on Localization and GNSS, at Gothenburg, Sweden, June 2015) discloses several methods, including correlation with the magnitude of acceleration (typically, the vertical component thereof), the peak and trough values of the acceleration waveform, and the variance of frequency of the steps taken to estimate step length. However, when taking single steps or very few steps at a time, the variance of walking appears to be ill-defined, thus problematic. Most of the approaches seem to not be able to make significant use of the horizontal acceleration components, although intuitively one would expect much useful information to be available from those axes.
In summary, it is evident that existing optical, navigation, and walking-distance technologies do not solve all of the principal problems addressed by the present invention. However, these technologies are often very useful at solving related problems, and many could gainfully integrated with the present invention.